I have been a member for perhaps over a year now and this thread is a big thank you/ take a look SPCR.
I've finally conquered my pc's noise.
northwood p4 2.4ghz
2x sata 300gb seagate 7200.7
This is my first silent PC. I started with a GMC-21 case and have to say i'd recomed these cases for build quality over anything else. Very solid (11kgs empty) and well made.
Anyway in it I put Four L1As front and rear, zalman cnps7000, a panaflo modded zalman 400b psu and a HIS IceQ 9800pro. I also modded the hdd cage to accept EAR gromits.
All fans were controlled by a rheobus and the setup was reasonably quiet however it was far from silent.. cooling was also inadequate and i ended up running with the side panel off most of the time.
Second attempt: Changed the cnps for a Ninja and bought four Yate-Loon D12SLs. Cut the front and rear grills to accomidate a 120mm fan. Mounted the Ninja and attempted hdd decoupling. I also setup a psu duct..
Cooling and noise improved dramaticly. With the fans at 5v the only remaing audible noise was coming from the hdds. I'm guessing there was too much tension in the elastic as i could still feel a good bit of vibration in the case and hdd whine was not that much quieter then with gromits.
Third attempt: Reattached the hdds with gromits, and decoupled the whole cage with foam rubber, elastic and cable ties.
Success! The hdd noise has stopped and there is no vibration that can be felt in the chassis. There is still a slight whine that i can't pin down but if i am not concentrating on it i tend to not notice. It does sound like a coil whine though so the prime suspect is the psu.
This is a gaming PC so the objective was always to have enough cooling with fans at 12v and silence at 5v, hence the choice of the yates (nexus fans, if you can find them, are almost $50 each here in NZ).
A huge thank you to MikeC and Ralf et al for all the guides, reviews and hard work this site contains. Yes its a little ghetto but I can now happily sleep in the same room as my pc
Thank you SPCR.